 In this video, Practice Problem 1, I'm asked to find the lateral area and the surface area of the square prism. And it gives me the dimensions of the base. I always like to start these off by writing down the formula for what the problem is all about. And as we get into more and more formulas this will be important to start off correctly. We're asked to find the surface area of the prism. And so I want you to start off by writing out that formula. I also like to start by shading the bases. And the reason that I do that is it can help you from making little simple errors as we go along. So you don't need to color it in but highlight or note that your base, you don't have to do both of them, maybe just one of them, is going to be the five by five that we're told in the problem. And once we do that it's easy to see then that the height of this prism is going to be the distance between the bases or the value of 12. The other thing that I like to do is write out all of the values that I need to plug into my formula B, P and H. So I'm going to do that off to the side here, B, P and H. And that way I can keep things organized and then just plug them all in at the end. You don't need to write this out but as you're starting out just to remind yourself what each of these values represents. The B represents the area of the base, P represents the perimeter of the base, and the H of course is the height of the entire prism. It's important to remember that B and P are both going to be values based on the base of your prism. And then the H is going to be that separate value, the vertical height between the two bases. And so let's go ahead and just calculate these out. The area of the base, the base is a square and we know the area of the square is just going to be length times width, 5 times 5 is 25. The perimeter of the base then is the distance around the base. And if this is a square, each side has a value of 5. And so it's just going to be 4 times the value of 5 or 5 plus 5 plus 5 plus 5. The distance around the base is 20. And then the height we already pointed out is the value of 12. And now that I have all three of those values to plug in, it will be a lot easier to just go ahead and plug them in. 2 times my base, 2 times 25 plus my perimeter times my height. Keep in mind too that if you're skipping this part of it and just plugging these values in, we see a lot of mistakes when that happens. So I would really recommend that you write down each of these values. Once you have everything to plug in, plug it in and then simplify. There are two separate terms here that we have to simplify before we add them together, basic order of operations. And so we're going to multiply each of those separately. 2 times 25 is 50. And then 20 times 12 is 240. Simplify those separately. And then when you add them up, 50 plus 240, my total surface area is 290. Make sure you're labeling these correctly. I'm not given any kind of measure on this problem. So when we don't know the measurement that is involved, we always are going to say units. And because it's surface area, it's going to be units squared. So I answered the total surface area, but I was also asked to find the lateral area of this prism. And so to finish my problem, I'm going to find the lateral area, which I already did because I did the calculation of 20 times 12. My lateral area perimeter times height was 240. And that again is area. So that would be units squared as well. Make sure you're paying attention to what they're asking for, total surface area or lateral area and giving the correct answer.